Question

If x^2+14x=51 and x>0, what is the value of x+7?

Answer 1

Answer:

x^2+14x=51

x^2+17x-3x-51=0

x(x+17) - 3(x+17) =0

(x-3) (x+17) =0

x = 3 , -17

but x>0 , so x = -17 will be discarded.

so x = 3

x+7 = 3+7 = 10